package com.hinotoyk.testsystem.uitls;

/**
 * @program: testsystem
 * @description:
 * @author: DYJ
 * @create: 2019-11-19 17:36
 **/
public class LevenshteinDistance {
    private static int min(int one, int two, int three) {
        int min = one;
        if (two < min) {
            min = two;
        }
        if (three < min) {
            min = three;
        }
        return min;
    }

    private static int ld(String str1, String str2) {
        int d[][]; // 矩阵
        int n = str1.length();
        int m = str2.length();
        int i; // 遍历str1的
        int j; // 遍历str2的
        char ch1; // str1的
        char ch2; // str2的
        int temp; // 记录相同字符,在某个矩阵位置值的增量,不是0就是1
        if (n == 0) {
            return m;
        }
        if (m == 0) {
            return n;
        }
        d = new int[n + 1][m + 1];
        for (i = 0; i <= n; i++) { // 初始化第一列
            d[i][0] = i;
        }
        for (j = 0; j <= m; j++) { // 初始化第一行
            d[0][j] = j;
        }
        for (i = 1; i <= n; i++) { // 遍历str1
            ch1 = str1.charAt(i - 1);
            // 去匹配str2
            for (j = 1; j <= m; j++) {
                ch2 = str2.charAt(j - 1);
                if (ch1 == ch2) {
                    temp = 0;
                } else {
                    temp = 1;
                }
                // 左边+1,上边+1, 左上角+temp取最小
                d[i][j] = min(d[i - 1][j] + 1, d[i][j - 1] + 1, d[i - 1][j - 1]+ temp);
            }
        }
        return d[n][m];
    }

    //返回两个文本的相似度
    public static double SIM(String str1, String str2) {
        try {
            double ld = (double)ld(str1, str2);
            return (1-ld/(double)Math.max(str1.length(), str2.length()));
        } catch (Exception e) {
            return 0.1;
        }
    }

}
    